recorded audio, is recorded in mono, for stereo sound you get two tracks laid down that are identical except for a 1db increase on the Left. That's how you get stero on cd's or even the FM transmission. If it were true stereo then if you only have one speaker on one channel then the only audio you will get is the audio thats "pan" to that side. Digital audio are being laid on top of analog cd's now due to the fact that some customers have digiatal playback devices which can take advantage of this but if you don't have the correct speaker placement then you are back to a regular analog playback.
Hope this helps
Nygel

Interesting, but that's not my understanding for digital music (perhaps it's true for radio). The stereo on a CD is multiplexed into a common data channel that's separated out int left and right stereo channels at playback, Source:

Streaming music services like Pandora and MOG use HE AAC v1 and v2 (= High Efficiency Advanced Audio Codec) so they can work at much lower bitrates than uncompressed CDs. iTunes downloads use AAC. (There's not much point using HE AAC unless you need to get under 128 kbps). In AAC and HE AAC v1 left and right channels use separate data streams. HE AAC v1 gives you good stereo quality down to about 48kbps.

The more recent HE AAC v2 achieves further compression by turning the left and right spacial information into metadata, so you have one single data channel (mono, if you will) and then metadata that tells the decoder how to spatially separate the data into left and right channels. This is called "parametric stereo". HE AAC v2 is only starting to get adopted. You can get very very good stereo audio quality down to about 32kbps with v2. If you play a track in HE AAC v2 through a phone or with only a HE AAC v1 compatible player you'll just get mono. Apple, Samsung and other handset makers have now adopted HE AAC v2 compatible decoders.